The drug substances, inclusive of the above-mentioned compounds, which have conventionally been employed for the treatment of gastric ulcer or duodenal ulcer, have several defects to be improved in terms of anti-ulcer activity, gastric-secretion suppressing activity and others.
The present inventors, with a specific view to finding a substance which exhibits improved anti-ulcer and gastric-secretion suppressing activities, conducted intensive research and as a result, have come to establish this invention.